Creeper-tractor.



UNITED STATES PATENT OFFICE.

WILLIAM TURNBULIlfOIE' PEORIA, ILLINOIS, ASIGNOR TO THE HOLT MANUFACTURING COMPANY, OF STOCKTON. CALIFORNIA, A CORPORATION OF CALIFORNIA.

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* Specification of Letters Patent.

Patented Mar. 4, 1919.

Original application filed December 11, 1916, Serial No. 186,208. Divided and this application filed March q 15, 1818. Serial No. 222,781.

To all whom it may concern:

Be it known that I, WILLIAM TunNnULL, a citizen of the United States, residin at Peoria, in the county of Peoria and tate of Illinois, have invented new and useful Improvements in Creeper-Tractors, of which the following is a specification.

This invention relates to endless link track vehicles and tractors, and has for its object to eliminate wear and slack of the links of the chain track when coming in contact with the blank idler wheel on the truck frame. I

In this type of maehine, which is fully described in my co-pending application Serial Number 136,208, of w ic this/i a divisional application, there are employed front and rear sprockets; the rear sprocket being the drive sprocket. the front or idler sprocket being blank and serving as a guide to conduct the track around the truck and beneath the supporting truck rollers in which the machine is carried. In all cases the tension to drive the machine is applied from the drive sprocket along the ground run of the track belt beneath the truck rollers, leaving more or less sag or slack in the up er idle portion of the track belt.

In this constr 'ction there is a tendency, especially when theehain has stretched, for the links to strike the blank idler wheel with some force resulting in increasml wear of the parts and causing considerable noise and clatter. Although the upper run of the chain is ordinarily supported upon guide rollers carried on the main tractor frame between the rockets, necessarily these upper guide rol ers being arrange some distance from the idler wheel and being mov-.

able relatively thereto, are inefiectlve to.

overcome the forcible striking of the links against the wheel and consequent vibration. I have discovered that b arranging a roller or other suitable gui e means comparatively close to the central oint of the upper ortion of the idler whee and mounting suc means on a support movable in accordance with the movement of the id]: wheel, this slapping of the links inst the wheel is overcome, and a desire tangential engagement of the links with the wheel is produced which results in a noiseless operation and reduces considerably the 1 ''Fig. 3 is a detail section of a track link pivotal connection.

In the drawings, I show a conventional form of tractor, embodyinge main frame 10 equipped with a roller truck mechanism comprising an endless chain track 11, carried upon a rear driving sprocket wheel 12. journaled upon the main frame, and a front blank idler Wheel 13,,journaled upon a roller truck frame 14, usually made in two articulated sections connected pivotally together at 15 and car ing a series of rollers 16 resting upon the ottom run of the chain track. The ma.'{.: frame is in this type of machine supported by means of springs 17 upon the roller truck frame. A series of guide rollers 18 is arranged beneath the upper run of the The chain track is made up of a series 9L9 articulated link sections, each com rising parallel side bars 20. the side bars 0 alternate links being connected together by gudgeon blocks 21 and the intermediate links being connected to the alternate links by means of pins 22 passing through the gudgeon blocks. The gudgeon blocks 21 engage the teeth on the sprocket wheel 12,

whereby the chain track is driven, and contact also w'tli the periphery of the blank idler wheel 13, whereas t e side bars straddle the rims'of both wheels; the bottom edges of the side bars on the up serum of the track being adapted tie-engage the guide rollers 18.

As will be Seen in Fig. 2, the cheiirtraek has a tendency to sag at the point 23 adjacent to the blank idler wheel, where there is no support between the nearest roller 18 and the central point of the upper portion of the idler wheel. '1herefore, the gudgeon blocks 21 strike the rim of the idler wheel in a direction somewhat radial thereto instead of tangential, as is desired. The efiect of this will be to permit a forcible collision between the idler wheel and links, which causes a cluttering noise and results in a quick wearing of the links. This clash will be increased when the mainframe and rol lens, 18 move relatively to the idler wheel 13 and its support.

I arrange guide rollers '24 one on elther side of the wl1eel'13 eomparativelyclose to the central point of the upper portion of the. wheel and journal these rollers upon a standard 25, carried on alink 25*, the latter connected to and preferably movable with i the journal boxes 13* ofthe blank idler wheel. The rollers 24 areflanged on their exterior sides and receive the chain between them and are preferably arranged with their upper surfaces a trifle higher than the upper surface of the blank idler wheel.

By reason of this arrangement the chain is supported at a point comparatively close to theoenter of the upper portion of the idler wheel, and this support is movable in unison with the wheel support The operation is indicated in Fig. 1 whereit will be. seen that the links comprising the chain, come into engagement with the idler wheel in a downwardly and forwardly inclined direction and tangential to the wheel. The clash is thus eliminated as is also eXccssivcL wear? There will be no forcible collision be mealtime links of the chain and-the rollers 24011 accouiit of the diil'erent manner in which the links engage the rollers. Here. the

I bottom edges of the side bars 20 rest at all times upon the peripheries of the rollers 24,

while on the idlerwieel 13 only the gndgeou blocks 21 engage with the peripherv and the;

side bars straddle the rim. Also, the links of thew-ham are tilted injthe diagram, and thus any tendency for i the rollers 94 and the ee tral point "on the the chain to sag is removed. The fact that tliii' rollers 24 are somewhat closer to the ad- "j'iitintroller 18 than the central point of the preupper portion of the idler wheel also vents any sagging of, the chain, the rollers 24 inefl merly' existed between the=jdler wheel-and the adjacent guide roller 18 It will be noted-thatth distance between upper portion fot-the er wheel rim esp proximates the lengthof one link ecti n,

fically or at this point, as showir i'na mc, a 'reurtdrivcl sprocket, which thema nfraine 1s yie'ldingly' su ect bridging the spaee which, for-.H

1,2es,a.12

and, thercforq, the chain cannot readily sa so asto perniit the links 'to slap the riiin o the idler wheel. 'lhese partsheing'ino'vahle in unison with each other will insure the proper engagement of thedinksWvith the idler wheel at all times, regardless of an rockinp or oscillation of the roller trutframe.

With the construction thus described the track is supported adjacent to the front sprocket by means of one or more floatin roilclswhich are so mounted as to move vertically or approximately so, in accordance with the vertical movements of the front of the truck; this form of cushioning meangor equivalent construction, providing in efiect a cushioning device and tangential suppdrii for theitraclc immediately ,vi eldi n gly supported, .a rear drive spiidcket wheel. a front idler wl eel mounted on "the. truck-frame, an endless, flexible, self-laying track passing around, the tii'o iwheels, and guide lllUtlllSdHljflCLllt the front Sprocket and pivotal ly nountediso as to'xnov e' iierwith the vertical movements of the frdrit of the truck. a

. In a tractor of the self-layin track t \'jlL'. the condmiation with a ma n rame, a

rear dl'H'L' sprocket monnmdfthereon, an articulated truck in line with the rear'lsprocket, springs interposed between the main. frame and the truck for yielding'lv supportjng the load on the truck. a front idler on the, truck, an endless. flexible. self-laying track s5 mg around said sprocket and idlfiif, and guide means,adjacenttqthe idler sprocket an pivotally, ,inounted to, more -vertically orapproximately so in flOQtHdtLllQG Wlpli the vertical movements of the front of the' tiiuck.

3. In ,a tractor. thecombinatiou of afmain a, truck on ported. a front idlerbn the track, an en less. self-laying track passingfaronnd' the sprm ket and idler, guide rollers "for an, .upper run o f ghetrac' mounted on tlijmain ,fraimn and a "floating roller mounted adjacent tel he idler ai dfcapabl .ofxen up and down lnoi'llliifififill' l qn th movements truck to dii eetfthtriiak tangentially ontotheidler.

principle of the approximately so I, in' laeeordancev sis t are 'sel f lay ing track type, the combination of a main frame, a .truck frame on wh ch the main "frame is 4. In a tractor, the combination of a main frmne, a rear drive sprocket, a truck on which the main frame is yieldingly su orted, a front idler on the truck, an en 5 ess, self-layi'ng track passin around the -sprocket and idler, guide 1'0 lers for the upper run of the track mounted on the main frame, a floating roller mounted adjacent to the idler and capable of an up and down 10 movement in unison with the movements of the truck to direct the track ta ntially onto the idler, and. meansby which 1; e floating roller maintains the same relativ pogition with ect to the front idler irrespective of the s 'fting of the position of the 15 idler on the truck. 7

In testimony whereof I have hereunto .set my hand in the presence of two subscribing wltn'.

WILLIAM TURNBUL Witnesses: v

LOUIS B. Nnumrnwxi, CARL A. FUNDAN. 

